Archive for January, 2016

Dr Curtis Cooper from the University of Central Missouri has found the largest-known prime number – written (274207281)-1. It is around 22 million digits long.

It was discovered thanks to GIMPS (Great Internet Mersenne Prime Search), a collaborative project of volunteers who use freely available software to search for primes. Mersenne primes are named after a French monk who studied them in the 17th Century.

Steve Humble MBE, of Newcastle University, writes that primes are strange and curious numbers. For example, there are no primes between 370,261 and 370,373, or between 20,831,323 and 20,831,533. And the primes 13,331, 15,551, 16,661, 19,991 and 72,227 and 1,777,771 are all palindromes (i.e.they remain the same when the digits are reversed).

Although computers do most of the hard work, primes are said to be discovered when a human takes note of the result. Which is awfully existential if you think about it…

NZ Transport Agency receives about ten noise complaints each month from people living near to an existing State highway. Complaints investigation can be a lengthy, costly and sometimes futile process. This is because retrofitting noise barriers or low-noise road surfacing is often unviable, leaving complainants dissatisfied. The resulting tension between parties highlights the need for consistent land-use controls; to manage the location of noise sensitive activities and to mitigate reverse sensitivity effects on the State highway network.

In case you missed it over the break, on 30 December 2015 the International Union of Pure and Applied Chemistry (IUPAC) verified the discovery of not one, not two, not three but four new elements. The 7th period of the periodic table of elements is now complete. The discoverers from Japan, Russia and the USA will now be invited to suggest permanent names and symbols.

Elements heavier than Rutherfordium (element 104) are referred to as superheavy. They are not found in nature, because they undergo radioactive decay to lighter elements. Those superheavy nuclei that have been created artificially have decay lifetimes between nanoseconds and minutes. But longer-lived (more neutron-rich) superheavy nuclei are expected to be situated at the centre of the so-called “island of stability”, a place where neutron-rich nuclei with extremely long half-lives should exist. Currently, the isotopes of new elements that have been discovered are on the “shore” of this island, since we cannot yet reach the centre.

The process of superheavy element creation and identification thus requires large-scale accelerator facilities, sophisticated magnetic separators, efficient detectors and time. Finding the three atoms of element 113 in Japan took 10 years, and that was after the experimental equipment had been developed.

The payback from the discovery of these new elements comes in improving models of the atomic nucleus (with applications in nuclear medicine and in element formation in the universe) and testing our understanding of atomic relativistic effects (of increasing importance in the chemical properties of the heavy elements). It also helps in improving our understanding of complex and irreversible interactions of quantum systems in general.